Extract number that comes before a certain word in an alphanumeric cell

Hi all,

I'm hoping someone can help me out. I'm looking for a function that extracts a set of number that comes before the word "trips" in an alphanumeric cell. The cells contain clutter of words and numbers that sometimes the number (that comes before the word "trips") is at the beginning of a cell or sometime it's at the end of a cell.
I did a bit of research and found a support page from MVP in ms office website but it doesn't give me the result that I need. http://office.microsoft.com/en-us/ex...001154901.aspx

Example:

E2 = 200 Trips - Structural
E3 = Wheel - 300 Trips

Result display:

F2 = 200
F3 = 300

Thank you in advance.
Cheers,
Pearl